With the rebirth of the spirit in man,by the dwelling of the Holy Spirit, is the only thing that saves his soul from damnation. God does not look or think twice about the flesh,because if he is going to put a new spirit in you, then that means that he have declared the flesh dead. Oh, it will do what it will do, except worship God.. That is why Jesus said that we must worship him in spirit and in truth. God knows that your flesh is sinful and weak,and cannot do the will of God. That is the purpose for being spirit filled with a clean spirit that can worship him. So you see, if you are spirit filled, no matter what the flesh does, it is dead, yes as dead as a rock. A perfect body would have meant totally destroying mankind and recreating them all over again.. God decided that he would condemn the flesh,kill it, and just renew the spirit, which is the only real way to worship him.